Is there a way to enter the absolute (not relative) value of a transformation?
Not entirely the answer you're looking for, but at least for some cases it works nicely to do one or more of the following:


Object > Clear > Location  Alt+G
Object > Clear > Rotation  Alt+R
Object > Clear > Scale     Alt+S


And after that make the transform and input the desired value. 

Also, it's important to mention that after pressing move G, rotateR or scale S, you can define:


global axis by pressing X,Y or Z
local axis by pressing XX, YY or ZZ.